JPH0338564A - Method for producing 4,4'-bis(4-aminophenylthio)diphenylsulfone - Google Patents

Abstract

PURPOSE:To obtain the subject compound in high yield and in high purity by blending an alkali metal salt of p-aminothiophenol heated to a specific temperature with 4,4'-dichlorodiphenylsulfone having specific purity and reacting the substances while maintaining a specific temperature. CONSTITUTION:1mol 4,4'-dichlorodiphenylsulfone having >=99.5% chromatography purity is added for 10 minutes to 2 hours to a solution of 2.1-5 mol alkali metal salt of p-aminothiophenol heated to 50-90 deg.C in an aprotic polar solvent, preferably N,N-dimethylformamide and both the substances are reacted for 30 minutes to 20 hours while maintaining temperature 60-100 deg.C, the reaction mixture is poured to water, precipitate is separated by filtration, washed with water to remove an organic salt, then washed with water to give the objective compound useful as a raw material for heat-resistant resin such as polyimide, a curing agent for epoxy resin and maleimide resin and a synthetic raw material for dye, drugs, agricultural chemicals, etc., industrially and advantageously.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention provides 4.4"-bis(4-aminophenylthio)
This invention relates to an improved method for producing diphenyl sulfone.

4.4゛-bis(4-aminophenylthio)diphenylsulfone can be used in polyamide, boria straw toimide, bori ξ
It is useful as a raw material for heat-resistant resins such as carbon dioxide, and as a curing agent for epoxy resins and maleimide resins.

It can also be used as a synthetic raw material for dyes, medicines, agricultural chemicals, etc.

(Prior Art) Conventionally, the following two methods are known as representative methods for producing aromatic diamines having a thioether bond.

(2) A method for reducing a di-toro compound obtained by the reaction of an alkali metal salt of an aromatic bisthiol with p-chloronitrobenzene (USSR Patent No. 478,831).

A method of reacting an alkali metal salt of o'p-aminothiophenol with an aromatic dihalogen compound (Japanese Unexamined Patent Publication No. 1983-1999)
No. 188365, No. 60-190755, and No. 6
2-289556).

The above method (2) has many problems, such as the fact that it is not easy to produce aromatic bisthiol as a raw material, and the reaction takes place in two stages, making the operation extremely complicated.

On the other hand, method (2) uses inexpensive raw materials, and by performing the reaction in an aprotic polar solvent, the reaction can be carried out in high yield.

(Problems to be Solved by the Invention) When 4,4゛-bis(4-aminophenylthio)diphenylsulfone is produced by the above method (①), problems such as coloring and a decrease in purity due to oxidation of the product arise. Therefore, in order to obtain a high-purity product suitable as a polymer raw material, a purification process such as recrystallization is required, and it cannot be said to be industrially preferable.

The present invention overcomes the above-mentioned problems, has high purity and high yield, and is advantageous for industrial implementation of 4.4°-bis(4-
The present invention aims to provide a method for producing aminophenylthio>diphenylsulfone.

(Means for Solving the Problems) That is, the present invention provides chromatographic purity of 99.5% or more.
'-Dichlorodiphenyl sulfone at a temperature of 50 to 90°C.
4,4゛-bis(4-aminophenylthio)diphenyl sulfone, which is characterized in that it is added to an alkali metal salt of p-aminothiophenol heated to a temperature of 60 to 100°C and then reacted. The present invention provides a method for manufacturing.

(4,4'-dichlorodiphenylsulfone) 4,4'-dichlorodiphenylsulfone used in the present invention has a purity of 99% by chromatography (liquid chromatography, gas chromatography, thin layer chromatography, etc.)
．． 5% or more. Note that 2,4'-dichlorodiphenyl sulfone may be contained as long as the content fiO is 5% or less.

<Alkali metal salt of p-aminothiophenol> The alkali metal salt of p-aminothiophenol used in the present invention is a combination of p-aminothiophenol and an alkali metal hydroxide, carbonate, alkoxide, hydride, alkyl It is prepared from basic alkali metal salts such as compounds. Among these, sodium hydroxide, potassium hydroxide,
Preferably, an alkali metal salt such as sodium carbonate or potassium carbonate is used.

The temperature for preparing the alkali metal salt solution of p-aminothiophenol is 0 to 220°C, preferably 20 to 180°C.
℃ range, the preparation time ranges from 10 minutes to 10 hours, preferably from 30 minutes to 3 hours. If water is produced as a by-product at this time, add a solvent that is azeotropic with water, is incompatible with water, and has a lower specific gravity than water, such as a hydrocarbon solvent, to co-produce water out of the system. It may be removed by boiling.

molar ratio> 4. For 1 mole of 4'-dichlorodiphenylsulfone,
The alkali metal of p-aminothiophenol is 2.1~
5 mol, preferably 2.4 to 3 mol.

Reaction solvent> In the present invention, for example, N,N-dimethylformamide,
Aprotic polar solvents such as N,N-dimethylacetamide, N-methylpyrrolidone, N-methyl-ε-caprolactam, tetramethylurea, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide can be used. preferable. Among these, it is more preferable to use N,N-dimethylformamide or N,N-dimethylacetamide.

The amount used is based on 100 parts by weight of the aromatic dihalogen compound and the alkali metal salt of p-aminothiophenol.
The proportion is 50 to 500 parts by weight.

Reaction Conditions> In the method of the present invention, 4.4'-dichlorodiphenylsulfone is added to the heated alkali metal salt of p-aminothiophenol, and then the reaction is allowed to proceed while heating.

4. The temperature at which 4'-dichlorodiphenylsulfone is added to the alkali metal salt of p-aminothiophenol is 50
~90°C, and addition times range from 10 minutes to 2 hours.

Since this reaction is an exothermic reaction, it generates intense heat with the addition of 4.4゛-dichlorodiphenylsulfone.
It is important to add while controlling the temperature to below 0°C. The reaction temperature is 60 to 100°C, preferably 70°C.
-100°C.

The reaction time is 30 minutes to 20 hours, preferably 1 to 5 hours. Note that this reaction is desirably carried out under an atmosphere of an inert gas such as nitrogen or argon.

<Post-treatment> By washing with tanol, 4,4"-bis (4-
Aminophenylthio)diphenylsulfone is obtained.

The diamine compound obtained here has sufficient purity and hue as a raw material for resin production at this stage.

(Effects of the Invention) According to the method of the present invention, the desired 4,4
°-bis(4-aminophenylthio)diphenylsulfone is obtained and is suitable for industrial production.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

<Example 1> A 21-meter four-eye flask was equipped with a thermometer, an ice separator with a Dimroth condenser, a nitrogen gas inlet, and a solid inlet.
p-aminothiophenol 300 g (2.4 mol), potassium carbonate 172.5 g (1.25 mol), N, N
-Dimethylformamide straw (hereinafter referred to as DMF) 100
0ml was charged and treated at 80°C for 1 hour to prepare p-aminothiophenol potassium salt.

Then, at 80°C, 244 g (0.85 mol) of 4,4'-dichlorodiphenyl sulfone (manufactured by Sanko Kagaku ■, liquid chromatography purity 99.9% or more) was added over 30 minutes.
The temperature was raised to 100°C and the reaction was carried out for 5 hours.

Then, it was washed four times with methanol 11 and dried in a vacuum oven at a temperature of 80°C.

By the above operation, 4,4″-bis(4-aminophenylthio>diphenylsulfone) was converted into a white solid, and 394.1
g (yield cJ9.9%) was obtained. In addition, the purity was measured by high performance thin layer chromatography (UV, 245/288 nm), the results were 99.4/99.1%, respectively.

(Examples 2 to 5. Comparative Examples 1 to 4) Various studies were conducted by changing the reaction solvent, addition temperature, reaction temperature, and reaction time. The results are shown in Table 1.

Claims (1)

[Claims] 4,4'-dichlorodiphenyl sulfone with a chromatographic purity of 99.5% or more was heated to a temperature of 50 to 90°C.
After adding to the alkali metal salt of aminothiophenol,
A method for producing 4,4'-bis(4-aminophenylthio)diphenylsulfone, characterized in that the reaction is carried out while maintaining the temperature at 60 to 100°C.